Yesterday the Norfolk Botanical Garden eaglets were banded by biologists from the Center for Conservation Biology at William & Mary. The timing of this procedure was very deliberate; scheduling the banding at a time when the eaglets are very docile, thereby minimizing any stress to the birds. The parents circled overhead, sometimes at a distance. Despite their size and fierce countenance bald eagles are actually fairly shy and the parents don't interfere with this type of procedure. The biologists who performed the banding are very experienced and able to perform the banding relatively quickly.
This type of work is instrumental in continuing to manage the recovery of bald eagles. The information gained from yesterday's banding will provide information regarding the ecology of bald eagles that will help inform the management decisions made in the future.
Once on the ground each eaglet was briefly examined and it vital measurements taken. A small blood sample was taken and a single feather collected. These will allow for future genetic work to be performed. A numbered aluminum band was placed around each eaglet's leg. These bands, which can be read at a distance with a spotting scope, will allow the future movements of these eaglets to be tracked, providing important information regarding the dispersal and habitat use of these birds. The bands are large enough to accommodate any growth. The eaglets didn't demonstrate any signs of distress or discomfort.
Following the banding each eaglet was returned to the nest. The parents have returned to the nest and are delivering fish.
Oldest Eaglet (Female)
The first eaglet banded was also the oldest. This eaglet is a female and weighed in at 3.815 kg (about 8.4lbs). The wing chord (from the "wrist" joint to the tip of the longest feather) measured 284 mm (or about 11 inches). Notice the numerous brown feathers growing in as the eaglet replaces down with juvenile feathers. Sex was determined by the relative size of the tarsus and feet.
The second eaglet banded was also the second hatched. This bird is a male and weighed 3.162 kg (6.9 lbs) with a wing chord of 272 mm (10.4 inches). The juvenile plumage was still obvious, but less progressed on this bird.
Middle Eaglet (male)
The final eaglet was also a male and the youngest of the three. This eaglet weighed 3.062 kg (also about 6.9 lbs). The wing chord of this bird was only 95 mm (3.7 inches). Why the disparity? This bird is younger and the growth of juvenile plumage not as advanced. There are really no primary feathers to speak of in this bird's wing, resulting in a much lower measurement. You can see the relative lack of juvenile plumage and the preponderance of down on this eaglet. This bird's crop was nice and full. Younger eaglets are more likely to retain food in their crop, whereas the older siblings simply gulp it down.